JP3836302B2 - Identification method and identification apparatus using identification marks - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for creating and identifying identification marks for various products, various artworks, jewelry, and the like.
[0002]
[Prior art]
Conventionally, a fluorescent material that emits visible light by excitation of ultraviolet light but cannot be visually recognized by visible light has been printed or applied to bills, securities, credit cards, artworks, jewelry, and the like. In this way, the invisible mark that does not clearly indicate the presence of the mark is irradiated with ultraviolet light in the dark where the visible light is shielded to emit the mark, and the presence or absence or shape of the mark is discriminated mainly visually and used for identification. can do.
[0003]
[Problems to be solved by the invention]
In the present invention, the above-described identification mark that cannot be visually recognized under visible light is hereinafter referred to as an invisible mark. As described above, in the conventional technique in which identification is performed by providing an invisible mark that does not clearly indicate the presence of the mark, when only the pattern of the invisible mark is used as an identification element, safety against the forged mark is sufficiently high. Absent. This is because when an article having a conventional invisible mark is irradiated with ultraviolet light, the existence and pattern of the mark are immediately revealed. When a fluorescent material having the same visible light emission color and the same pattern as that of the mark is applied or dyed and visually determined, the counterfeit article is also due to the low emission luminance of the phosphor. Is difficult to identify. In particular, there are articles, precious metals, and jewelry that have complex shapes in the articles that you want to identify authenticity, but many of these articles have complex and small shapes other than flat shapes. It was difficult to apply to articles.
[0004]
[Means for Solving the Problems]
In the present invention, an identification mark using a fluorescent material that emits light only by excitation with excitation light such as ultraviolet light is fixed or dyed by printing, coating, or other methods on an article that requires identification, and irradiation with a plurality of excitation lights This is an identification mark technique for identifying the article by causing it to emit light. More specifically, a plurality of types of fluorescent materials are mixed at a predetermined mixing ratio, and fixed or dyed on an article to be identified. The fluorescence spectrum emitted from such a mixed fluorescent material emits a spectrum peculiar to the type and mixing ratio of the mixed fluorescent material. Therefore, by spectroscopically measuring the fluorescence emission, an article with an identification mark can be quickly and accurately identified.
[0005]
Further, two or more kinds of excitation light are irradiated on the article with the above identification mark to obtain a fluorescence spectrum, and two or more kinds of fluorescence spectra obtained therefrom are dispersed to obtain intensity spectrum data. If processing is performed to display a two-dimensional pattern, the same two-dimensional pattern is always generated as long as the same identification mark is irradiated with the same combination of excitation lights. This two-dimensional pattern figure includes a characteristic fine structure corresponding to the combination of the identification mark and the excitation light. It is known that human visual recognition has the ability to quickly discriminate even a minute difference for a two-dimensional pattern figure. Therefore, an identification mark can be attached to the display by converting the intensity spectrum data of the identification mark by two or more kinds of excitation light into a two-dimensional pattern by utilizing the advanced ability of human pattern graphic recognition. It is possible to quickly and accurately identify the article that has been used.
[0006]
In the present invention, a plurality of types of fluorescent materials are mixed and used at a predetermined mixing ratio as the fluorescent material for identification. Therefore, the fluorescence spectrum emitted from now on emits a unique spectrum determined by the type and mixing ratio of the mixed fluorescent material. A great variety of fluorescent materials are known, ranging from inorganic materials to organic materials. Among them, there are many types of materials that can be used industrially, stably, safely and inexpensively. Moreover, in the present invention, since these substances are mixed and used at a predetermined mixing ratio, there are an infinite number of spectrum combinations. Therefore, it is practically impossible for a person other than the person who produced the mixed fluorescent material to reproduce the same fluorescence spectrum as that emitted by the mixed fluorescent material with a mixture of some other substance. Thus, according to the present invention, it is possible to synthesize the same fluorescent spectrum as the mixed fluorescent material, except for those who know the mixed fluorescent material used for the mark used for identifying the article and the mixing ratio thereof. Almost impossible. Therefore, the confidentiality of the identification mark and the reliability with respect to the difficulty described later are great.
[0007]
In particular, when the fluorescence spectra of the individual fluorescent materials of the mixed fluorescent material overlap completely or partially, the fluorescent spectra of the mixed fluorescent material are synthesized. In such a case, since it becomes more difficult to reproduce the synthesized fluorescence spectrum with a fluorescent substance other than those constituent elements, further improvement in identification reliability according to the present invention can be expected.
[0008]
Depending on the article in which the identification mark is used, there are cases where it is necessary or preferable that the mark is visible under normal visible light illumination, and cases where it is inconvenient or undesirable. For example, in order to prevent the production of counterfeits, clearly indicating that the article has a function that can be identified with an identification mark, as in the case of the presence of banknotes and securities. Where useful, the marks may be colored, usually under visible light illumination. Thus, even if the existence of the identification mark is clearly indicated, according to the present invention, a person other than the manufacturer of the article who knows the type of the mixed fluorescent material used for the mark and the mixing ratio thereof can use such a mark. As mentioned above, it is almost impossible to reproduce in the function of identification, so that it will not have a particular disadvantage.
[0009]
On the other hand, the visual recognition of the identification mark under normal visible light illumination may be inconvenient. For example, if an article that needs to be identified depends on the color of the article itself, such as a work of art or jewelry, the mark can be seen even on a part of the article. The original aesthetic value of the article may be impaired. In such a case, the identification mark of the present invention can achieve its purpose if it emits fluorescence of ultraviolet light or visible light only by ultraviolet light excitation, for example, and can be colorless and transparent under normal visible light illumination and Preferably, in that case, the aesthetic value of art and jewelry is not reduced.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a spectrum diagram showing a spectrum of a light source, an absorption spectrum of a fluorescent substance, and a fluorescence emission spectrum used in an embodiment of the present invention. In the figure, spectra E and E ′ are the spectra of the excitation ultraviolet lamp, the horizontal axis represents the wavelength λ, and the vertical axis represents the intensity, and shows the line spectrum of a commonly used mercury vapor discharge ultraviolet lamp. The ratio of the peak intensities of E and E ′ is usually determined by the substance. In the case of a mercury vapor discharge ultraviolet lamp, the wavelength of E is 254 nm, and the center wavelength of E ′ is 365 nm. The spectra A1 (λ), A2 (λ), A3 (λ),... Indicate the absorption spectra of the individual fluorescent materials constituting the mixed fluorescent material of the present invention. The relative proportions of these absorptions are determined by the type and mixing ratio of the individual fluorescent materials. In addition, in order for individual fluorescent substances to emit fluorescence, their absorption spectra A1 (λ), A2 (λ), A3 (λ),... Are at least one of the excitation ultraviolet light spectra E and E ′. Or overlap on both. Spectra F1 (λ), F2 (λ), F3 (λ),... Are fluorescence emission spectra of individual fluorescent substances constituting the mixed fluorescent material, and F (λ) is indicated by the mixed fluorescent material. A fluorescence emission spectrum, which is usually represented by the spectra F1 (λ), F2 (λ), F3 (λ),.
[0011]
F (λ) = F1 (λ) + F2 (λ) + F3 (λ) + (1)
[0012]
And the sum of the emission spectra of the individual fluorescent materials. However, the spectrum F (λ) is a value normalized with respect to the maximum wavelength.
[0013]
The shape and relative height of the individual fluorescence spectra F1 (λ), F2 (λ), F3 (λ),... Are the intensity of the excitation ultraviolet spectrum, and the absorption spectra A1 (λ), A2 ( λ), A3 (λ),..., are determined by relative positions on the wavelength. Therefore, it is determined by determining the type of excitation ultraviolet light source, individual fluorescent materials, and their mixing ratio. Therefore, the shape F (λ) of the fluorescence emission spectrum of the mixed fluorescent material is determined if the excitation ultraviolet light source, the individual fluorescent materials, and the mixing ratio thereof are determined.
[0014]
FIG. 1 shows a case where F1 (λ), F2 (λ), F3 (λ),... Are particularly overlapped with respect to the wavelength. From the shape F (λ), it is practically impossible to identify the individual phosphors used and the mixing ratio. Thus, when F1 (λ), F2 (λ), F3 (λ),... Overlap with respect to the wavelength λ, it is particularly excellent in the confidentiality of the individual fluorescent materials used and the mixing ratio. ing.
[0015]
In order to use the fluorescence emission spectrum shape F (λ) as an identification mark, F (λ) is measured with a spectroscope while irradiating the identification mark with a mercury vapor discharge ultraviolet lamp having excitation spectra E and E ′. The article provided with the mark is identified by visually observing on the display monitor whether or not it matches the spectrum. Until the fluorescence emission spectrum shape F (λ) is displayed on the display monitor, F (λ) is converted into a display electric quantity by a photodetector, an amplifier (not shown) or the like. The dependence of the quantities of electricity being converted on the wavelength is always kept constant by initial calibration and computer processing of those quantities of electricity.
"Example"
Next, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 2 is a block diagram showing the configuration of the embodiment of the present invention. Reference numeral 1 denotes a mercury vapor discharge ultraviolet lamp for emitting ultraviolet light 2 and irradiating the sample 3. The sample 3 irradiated with the ultraviolet light 2 emits fluorescence 4, and the fluorescence 4 is dispersed by the spectroscope 5. Three emitted fluorescence spectrum data are collected. 61 and 62 are filters for separating and selecting excitation spectra E and E ′ emitted from the mercury vapor discharge ultraviolet lamp, 7 is a data processing computer for obtaining an identification pattern from the obtained spectral data, and 8 is a visual recognition of the identification pattern. This is a display monitor for displaying an identification pattern for confirmation by the above. Since the fluorescent material sample 3 does not damage the object to which the fluorescent material sample 3 is attached, it is preferable that the fluorescent material sample 3 has a very small area, for example, a radius of about 0.3 mm.
[0017]
FIG. 3 shows an excitation spectrum, an absorption spectrum, and a fluorescence emission spectrum in this example. Excitation spectra E and E ′ emitted from the mercury vapor discharge ultraviolet lamp are selectively separated by the filters 61 and 62, and the shape FE (λ) of the fluorescence emission spectrum when excited with is excited in FIG. The shape FE ′ (λ) of the fluorescence emission spectrum in this case is shown in FIG.
[0018]
In the measurement performed by separating the excitation spectra E and E ′, the numerical values of the wavelengths λ of the obtained spectrum data FE (λ) and FE ′ (λ) are respectively set to the two-dimensional coordinates x and y. Used and denoted as FE (x) and FE ′ (y). These spectral data FE (λ) and FE ′ (λ) are both normalized with respect to their maximum values, as is the case with F (λ) in equation (1) above. Next, a two-variable function G (x, y) is synthesized from these spectrum data FE (x) and FE ′ (y). This composite function is generally
[0019]
G (x, y) = f [FE (x), FE ′ (y)] (2)
[0020]
It is expressed. When such a two-variable function G (x, y) is displayed on the display monitor 8, G (x, y) can be visually recognized as a two-dimensional pattern on the monitor 8. Such a two-dimensional pattern generally draws a figure having characteristics as shown in FIGS. As a result, you can easily see even the finer differences much more quickly than seeing the match of the raw data FE (λ) and FE ′ (λ) directly obtained from the measurements for each given spectrum. Can be used for quick and accurate identification.
[0021]
An example of a suitable function form of the composite function of the expression (1) described above is as follows.
[0022]
G (x, y) = FE (x) · FE ′ (y) (product function) (3)
G (x, y) = FE (x) / [FE ′ (y) + c] (quotient function) (4)
G (x, y) = FE (x) + FE ′ (y) (sum function) (5)
G (x, y) = FE (x) −FE ′ (y) (difference function) (6)
G (x, y) = [FE (x)] ² + [FE ′ (y)] ² (square sum function) (7)
G (x, y) = [FE (x)] ² − [FE ′ (y)] ² (square difference function) (8)
G (x, y) = [FE (x) + FE ′ (y)] ² (sum square function) (9)
G (x, y) = [FE (x) −FE ′ (y)] ² (difference square function) (10)
[0023]
In addition, logarithmic display thereof may be considered, but any other function that is a bounded function and emphasizes a fine difference as a pattern may be used. From the viewpoint of economic efficiency in computer processing, the above example is preferable, and among them, the one shown at the top is more economical. In the case of equation (4), a small constant is added to the denominator to prevent divergence.
[0024]
These composite functions are generated by the data processing computer 5.
The display method of G (x, y) for improving the visibility of the composite function G (x, y) displayed on the display monitor 7 is contour line display, gray scale display, contour line + gray scale display, contour line. Or the pseudo color display corresponding to a gray scale was suitable. These processes are performed by the computer 5 and are appropriately switched and displayed on the display monitor 6 according to an instruction from an operation instruction device such as a keyboard or a mouse attached to the computer. When fine identification is required, the most suitable display method can be quickly selected.
[0025]
In FIG. 4, as an example, from FE (x) and FE ′ (y), the product function G (x, y) = FE (x) · FE ′ (y ) Is an identification pattern obtained when contour lines are displayed. In the figure, FE (x) is shown along the x-axis, FE ′ (y) is shown along the y-axis, and the corresponding identification pattern G (x, y) of those product functions is shown in the figure. Shown to be synthesized.
[0026]
FIG. 5 shows an equation (4) that is a quotient function of FE (x) and FE ′ (y), and FIG. 6 shows an equation (5) that is a difference function between FE (x) and FE ′ (y). The identification patterns when contour lines are displayed are shown. From such a characteristic identification pattern, it is possible to obtain a display in which the fine characteristics of the identification mark designed by the user can be confirmed accurately by visual recognition. From such a characteristic identification pattern, it is possible to obtain a display in which the fine characteristics of the identification mark designed by the user can be confirmed accurately by visual recognition. In FIGS. 5 and 6, illustration of the respective functions along the x-axis and the y-axis is omitted, but similar to FIG. 4, each function corresponds to a product function represented by a pattern.
[0027]
Since such a two-dimensional pattern is displayed through a step of normalizing the original data, the pattern itself does not change even if the mixed fluorescent material is decreased with time. Therefore, such an identification mark can be used for a long time.
[0028]
As described above, specific examples of the mark for identification and the apparatus therefor according to the present invention have been described. However, an easy modification or development made by a person familiar with the related field can be inferred from these examples. When it is determined that the present invention is within the spirit of the present invention, it is within the scope of contribution of the present invention to this field. Accordingly, such modifications and developments are also legally and properly included within the scope of this patent.
[0029]
【The invention's effect】
According to the present invention, if the individual fluorescent materials as the components of the mixed fluorescent material of the excitation light source and the identification mark and the mixing ratio thereof are determined, the emission spectrum shape from the mark can be determined from the spectral principle. It depends on the light source intensity and the brightness of the spectroscope used. Therefore, identification of an article having an identification mark according to the present invention is always performed with high reliability. Moreover, since it is difficult to identify the constituent materials of the identification marks and their mixing ratio from the spectrum, the secrecy and reliability are high, and two or more spectral data obtained by switching the excitation light source This two-dimensional pattern identification enables a quick and accurate identification operation. Therefore, a system capable of rapid identification with high reliability can be put into practical use.
[Brief description of the drawings]
FIG. 1 is a diagram showing an excitation light spectrum, an absorption spectrum, and a fluorescence emission spectrum for explaining the operation of an identification mark according to an embodiment of the present invention.
FIG. 2 is a block diagram of an identification apparatus showing an embodiment of the present invention.
FIG. 3 is an excitation light spectrum, an absorption spectrum, and a fluorescence spectrum diagram for explaining the operation of an identification mark according to an embodiment of the present invention.
FIG. 4 is an identification pattern by contour display of a product function.
FIG. 5 is an identification pattern by contour display of a quotient function.
FIG. 6 is an identification pattern by contour display of a difference function.
[Explanation of symbols]
λ Wavelength E, E ′ Excitation light spectrum A1 (λ)
A1 (λ), A2 (λ), A3 (λ), ... absorption spectrum A3 (λ)
F1 (λ), F2 (λ), F3 (λ), ... Fluorescence emission spectrum F (λ) Fluorescence emission spectra FE (λ) and FE '(λ) exhibited by mixed fluorescent materials Excited by E and E', respectively Fluorescence spectra FE (x) and FE ′ (y), respectively, fluorescence spectra G (x, y) excited by E and E ′, two-variable synthesis function 1 mercury vapor discharge ultraviolet lamp 3 sample 5 spectrometers 61 and 62 Filter 7 Data processing computer 8 Identification pattern display display monitor

Claims (8)

A method for identifying an identification mark including a mixed fluorescent material obtained by mixing a plurality of types of fluorescent materials,
The identification mark formed on the article is irradiated with two types of excitation light having different excitation spectra, and two fluorescence spectra FE (λ) and FE ′ (λ) (where λ represents the wavelength of the excitation light). Collect and
From the two fluorescence spectra FE (λ) and FE ′ (λ), a variable λ is a variable x and y, and a two-variable synthesis function f (FE (x), FE ′ (y)) is created.
An identification method for displaying the variables x and y as two-dimensional coordinates and the two-variable synthesis function as a two-dimensional pattern.   The identification method according to claim 1, further comprising: normalizing the collected fluorescence spectrum by a maximum intensity value therein and generating the composite function from the two kinds of normalized fluorescence spectra.   The identification method according to claim 1, wherein fluorescence spectra of the plurality of types of fluorescent materials have a wavelength range in which the whole or part of the spectrum is overlapped.   The identification method according to claim 1, wherein the fluorescent material is an ultraviolet-excited fluorescent material. An identification device for an identification mark including a mixed fluorescent material obtained by mixing a plurality of types of fluorescent materials,
A light source unit that generates two types of excitation light having different excitation spectra;
The identification marks formed on the article are each irradiated with the two types of excitation light to collect two fluorescence spectra FE (λ) and FE ′ (λ) (where λ represents the wavelength of the excitation light). A spectroscopic device;
Data for creating a two-variable synthesis function f (FE (x), FE ′ (y)) from the two fluorescence spectra FE (λ) and FE ′ (λ), where the wavelength λ is a variable x and y, respectively. A processing device;
A display device that displays the two-variable composite function as a two-dimensional pattern with the variables x and y as two-dimensional coordinates.   6. The identification device according to claim 5, wherein the data processing device normalizes the collected fluorescence spectrum by a maximum intensity value therein, and creates the composite function from the two types of normalized fluorescence spectra.   The identification method according to claim 5 or 6, wherein fluorescence spectra of the plurality of types of fluorescent materials have a wavelength range in which the whole or part of the fluorescence spectrum overlaps.   The identification device according to claim 5, wherein the fluorescent material is an ultraviolet light-excited fluorescent material.

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